Walking assist devices are being researched which assist the walking of a user by actively applying torque to a joint of a leg, thereby adjusting an angle of the leg. For example, Patent Document 1 discloses a walking assist device worn by a user who cannot move one leg well, which applies torque to a joint of the unhealthy leg based on a motion of a healthy leg.    [Patent Document 1] Japanese Patent Application No. 2006-314670